EXCLUSIVE: Showing just how fiercely competitive the slumping box office is right now, Warner Bros is griping to me about how rival movie studios are reporting their North American numbers this holiday week. These kind of controversies don’t develop often in Hollywood, but when they do, they can be ugly. The Warner Bros complaint is over both Paramount and Sony reporting Tuesday’s eveing grosses as part of Wednesday’s midnight take for Mission: Impossible – Ghost Protocol and The Girl With The Dragon Tattoo respectively. Nobody is disputing the accuracy of the figures. Just where and when the money is accounted. That’s because there is a certain code of honor among these Hollywood thieves — a tacit agreement that every studio will try to report box office numbers as accurately as possible. But there’s also a significant PR advantage to artificially moving a disappointing film up a slot in the Top 10 by inflating numbers. Warner Bros is especially touchy because its sequel Sherlock Holmes: A Game Of Shadows was supposed to be the big Christmas-New Years movie and instead opened to disappointing domestic grosses last weekend. Since then it’s been holding well. But Warner Bros points out that Sherlock should have been #2 for Wednesday if the two rival studios hadn’t combined Tuesday evening’s numbers with Wednesday’s numbers. That’s not considered fair play, as this WB exec’s email to me shows:

The real news Wednesday night was how well Sherlock is holding. MI4 opened wide on Tuesday at 5PM and included the entire day ($2M) into Wednesday’s gross of $8.5M. Tattoo opened wide at 7PM on Tuesday and included the entire day ($1.6M) into Wednewsday’s gross of $5M. Since this creative reporting has never be done before, you should note that both films grosses Wednesday night were intentionally inflated from $6.5M and $3.4M respectively. Sherlock’s 6th day actually finished in 2nd place Wednesday. Let’s all compete on a level playing field. Just watch the drop off Thursday of both M:I4 and Tattoo vs Sherlock.